Cross-post to skinmaan's Smashwords summer sale thread. I went through and looked for mysteries. I'm not done looking, but have other things to do, so I posted what I found so far in that thread. Mostly the usual titles that go on sale via Smashwords, but there may be a few in there of interest.
link:
https://www.mobileread.com/forums/sho....php?p=3345447